1. Field of the Invention
The present invention relates to an electrical connector, and more particularly to a modular jack with foolproof member for permitting proper insertion of a full sized plug and preventing erroneous insertion of an undersized plug.
2. Description of the Prior Art
Modular jacks and plugs for use in the communications and computer industries are well known. Nowadays, there are generally two types, that is, smaller sized RJ-11 jacks and plugs and larger sized RJ-45 jacks and plugs. Of course, each of these kJ-11 and RJ-45 jacks are intended to receive only an RJ-11 or RJ-45 plug, respectively. However, the RJ-11 and RJ-45 jacks are often located side by side and frequently placement of the RJ-11 and RJ-45 jacks within electronic equipment is in a location which does not lend themselves to easy visual inspection. Thus, it is possible that during blind installation of a plug into a jack, an operator may incorrectly align an RJ-45 plug with an RJ-Il jack or an RJ-11 plug with an RJ-45 jack. In actual use, due to the size differential, misaligning an RJ-45 plug with an RJ-11 jack is of little concern because an operator will quickly notice that the RJ-45 plug is larger than a plug receiving cavity of the RJ-11 jack. However, misalignment of an RJ-11 plug with an RJ-45 jack creates a serious concern. The RJ-11 plug will fit within the RJ-45 jack, often quite comfortably. In such an event, an operator will actually hear audible click of the RJ-11 plug latch snapping into place within the RJ-45 jack and feel what seems to be proper mating of a plug within a jack. Moreover, the RJ-11 plug will be inserted far enough into the RJ-45 jack to allow contacts of the RJ-11 plug to electrically engage terminals of the RJ-45 jack. This can lead to severe damage to the electronic equipment because certain RJ-11 plug contacts may be carrying higher current than the electronic equipment circuitry which is intended to receive from a respective electrically engaged RJ-45 jack terminal. Accordingly, providing an RJ-45 jack which can effectively prevent errouneous insertion of an RJ-11 plug is conspicuously needed.
One method of addressing the above-mentioned problem is provided in U.S. Pat. No. 6,296,528 B1 which discloses a modular jack with feature for selectively restricting plug insertion. A stop surface is provided incorporated with a flexible stop member. A more forwardly positioned sliding surface is provided also incorporated with the flexible stop member. When an undersized plug is inserted into the modular jack, a leading edge of the undersized plug contacts the stop surface and is prevented from full insertion. When a full sized plug is inserted into the modular jack, a leading edge of the full sized plug contacts the sliding surface before reaching the stop surface and causes the sliding surface to move relative to the leading edge of the full sized plug. The movement produces a subsequent movement of the flexible stop member and the stop surface incorporated thereon, such that the stop surface is located out of engagement with the leading surface of the full sized plug, and full insertion of the full sized plug into the modular jack is permitted. However, the single cantilevered flexible stop member seems too weak to take on restricting function when the undersized plug is inserted into the modular jack. The flexible stop member has a great chance of break down when exerted by a strong insertion force of the undersized plug or repeatingly attempt to insert the undersized plug into the modular jack.
Another method of addressing the above-mentioned problem is provided in Kameya et al., U.S. Patent Publication No. 2002/0146114 A1 which discloses a modular jack. The modular jack comprises an insulative housing and a pair of foolproof member provided on an upper portion of the housing. Especially referring to FIG. 3 of Kameya et al., the housing defines a pair of horizontal grooves at a top wall thereof, a pair of vertical slots communicated with front ends of the grooves and a pair of vertical slits communicated with rear ends of the grooves. Each foolproof member comprises a fixing section press-fitted in the vertical slit to secure the foolproof member in position, a flat spring section extending along bottom of the horizontal groove, and an abutment section located in the vertical slot. The abutment section has a cam portion and a stopper portion located behind and inside the cam portion. Similar to the above description, when an undersized plug is inserted into the modular jack, a leading edge of the undersized plug abuts against the stopper portions to prevent fully insertion of the undersized plug. When a full sized plug is inserted into the modular jack, a leading edge of the full sized plug contacts the cam portions to move the abutment sections upwardly, permitting fully insertion of the full sized plug. However, a problem exists with the modular jack in that fixation between the fixing sections of the foolproof member and the vertical slits of the housing greatly increases the complexity resulting in a complicated assembling process. Additional, especially referring to FIGS. 7A–7C of Kameya et al., it should be pointed out that when the leading edge of the full sized plug abuts on the cam portions to move the abutment sections upwardly, the movement produces a subsequent movement in the flat spring sections which ultimately show themselves in an inclined station, thereby causing the fixing sections to lean to forwardly incline. However, during the spring sections moving upwardly, since the fixing sections press-fit into the vertical slits and should not occur any movement, resistive forces will be inevitably created and transferred to the connections between the flat spring sections and the fixing sections, thus the connections are inclined to fatigue and will become more prominent after a period use so as to unfortunately break.
Hence, a modular jack with an improved foolproof member adapted for permitting proper insertion of a full sized plug and preventing erroneous insertion of an undersized plug is desired to overcome the disadvantages of the prior arts.